The Rockstar one a few years back was great. Got $60 worth of credit just for "drinking energy drinks".
By far the best for me. I got, ballpark, about $240 in credit from that one. I was lucky to know two people who don’t game that drank them daily and would collect their tabs for me. Plus I was already drinking them anyway too. Man that was a lot of code entries, two codes to enter for every reward! But so worth it!